Crowdsale

Understanding the Ethereum contracts for the Globatalent crowdsale

Technical definition

ERC20-compliant token, derived from the MiniMe Token that allows for token cloning (forking).

Contracts

Addresses

Token: 0xd8bd3958725f216eb236e9dc65b169de48101c6a
TokenContribution: 0xf8a06ef897755bbd49707d8a8ce0ca9e6a0f0c34
AdvisorsTokensHolder: 0x17cffeda91185b35d57d4cd1b4e2f861a760af16
AirdropTokensHolder: 0x49820e81d4d562f2cfbb9854c97ab43fb09a2d10
BountiesTokensHolder: 0xef47c51a6c1c5c42f13b3539d0421fcbc84ed24c
EarlyInvestorsTokensHolder: 0x483572613a2283de274dfd6f7ae85d67aef70dfe
ReserveTokensHolder: 0x05bd9302216f862a1aca5b2c8d16f463290048c4
TeamTokensHolder: 0xe31bb9b1b4a4e7c7c1df5b2e10f314697e5f802c

Utilities

Controlled.sol

This contract provides useful methods to establish the address that can call functions of another contract.

onlyController() [L6]: Checks that the address calling the function equals the controller address.
controller [L8]: Controller address.
Controlled() [L10]: Contract constructor. Sets controller variable to the address that creates the contract.
changeController(newController) [L14-L16]: The actual controller can call this function to change controller to newController.

Owned.sol

onlyOwner() [L10]: Checks that the address calling the function equals the owner address.
owner [L15]: Owner address.
Owned() [L19]: Contract constructor. Sets owner variable to the address that creates the contract.
newOwner [L22]: Address of the new owner.
changeOwner(newOwner) [L27-29]: Old owner can call this function to set a newOwner.
acceptOwnership() [L32-L36]: If there is a new owner and calls this function the new owner is accepted as the owner of the contract.

SafeMath.sol

mul(a, b) [L8-12]: Multiplies two numbers checking for overflows.
div(a, b) [L14-19]: Divides two numbers checking for overflows and zero divisions.
sub(a, b) [L21-24]: Does a subtraction checking a is greater or equal than b.
max64(a, b) [L32-34]: Checks the maximum between two 64 space numbers.
min64(a, b) [L32-34]: Checks the maximum between two 64 space numbers.
max256(a, b) [L40-42]: Checks the maximum between two 256 space numbers.
min256(a, b) [L4-46]: Checks the maximum between two 256 space numbers.
percent(a, b) [L48-50]: Does the percentage between a and b.

Token specific:

ERC20Token.sol

Interface for ERC20 compatible tokens.

totalSupply [L16]: Variable that contains the total supply of the token.
balanceOf(owner) [L20]: Returns the token balance of the owner.
transfer(to, value) [L26]: Transfers value amount of tokens from your account to to another account.
transferFrom(from, to, value) [L33]: Transfers value amount of tokens from one account to another.
approve(spender, value) [L39]: Approves someone to spend value amount of tokens from your account.
allowance(owner, spender) [L44]: Checks the amount of tokens a person has authorized another to spend from his account.
Contract events [L46-47]: Events to log event from smart contract.

TokenController.sol

Our token contract allows a token controller, this way we can upgrade functionality and modify it's behaviour.

proxyPayment(owner) [L8]: Method to call sending ether to purchase tokens.
onTransfer(from, to, amount) [L16]: Method called when transferring tokens, let’s us control when tokens can start to be tradable.
onApprove(owner, spender, amount) [L24]: Method called when someone approves another person to spend tokens from his account.

MiniMe token follows the ERC20 standard and implements all the functions described on ERC20Token.sol but since more logic is required by this token it breaks ERC20 functions into more than one method.

name [L40]: Name of the token.
decimals [L41]: Decimals of the token.
symbol [L42]: Symbol of the token.
version [L43]: Version of the token.
Checkpoint [L49-56]: Struct with two variables which is used to store the amount of token supply at a certain block.
parentToken [L60]: Address from which the token has been cloned, if it’s not been cloned it will be 0x0.
parentSnapShotBlock [L64]: Block number to determine the initial distribution of the parent token if actual token was cloned.
creationBlock [L67]: Block number when the token was created.
balances [L72]: Map that tracks the amount of token of/to an address
allowed [L75]: Map that stores the amount an address can transfer from another account.
totalSupplyHistory [L78]: Array that stores the history of the token at certain blocknumbers.
transfersEnabled [L81]: Determines if the token is transferable.
tokenFactory [L84]: Factory used to create new clone tokens.
MiniMeToken(tokenFactory, parentToken, parentSnapShotBlock, tokenName, decimalUnits, tokenSymbol, transfersEnabled) [L103]: Contract constructor.

See MINIME_README.md for more information.

[ERC20 methods]

doTransfer [L167]: Actual transfer function in this contract. Inside it, balances are checked. The TokenController is warned that a transfer has been done and it checks that transfers are enabled.
totalSupply(blockNumber) [L270]: Returns the total supply of tokens at blockNumber.
balanceOfAt(owner, blockNumber) [L283]: Returns the amount of tokens of owner at blockNumber.
createCloneToken(cloneTokenName, cloneDecimalUnits, cloneTokenSymbol, snapshotBlock, transfersEnabled) [L344-366]: Creates a new clone token with the initial distribution being this token at snapshotBlock.
generateTokens(owner, amount) [L376-386]: amount number of tokens are asigned to owner. This method can only be called from the controller of the token.
destroyTokens(owner, amount) [L393-403]: Burns amount tokens from owner.
enableTransfers(transfersEnabled) [L412-414]: Sets transfers enabled.
getValueAt(checkpoints, block) [L424-445]: Returns the number of tokens at a given number block.
updateValueAtNow(checkpoints, value) [L451-461]: Updates the history of balances.
isContract(addr) [L467-474]: Internal function to determine if addr is a contract. min(a, b) [L477-479]: Determine the minimum between two uints.
Default function [L484-487]: The fallback function: If the contract's controller has not been set to 0, then the proxyPayment method is called which relays the ether and creates tokens as described in the token controller contract.
claimToken(token) [L497-507]: This method can be used by the controller to extract mistakenly sent tokens to this contract.
Events [L512-521]: Events used by the contract to emit values.
MiniMeTokenFactory [L531-563]: This contract is used to generate clone contracts from a contract.

Token.sol

Inherits from: MiniMeToken. This creates an instance of MiniMeToken with the desired parameters to customize the token.

Contribution

TokenContribution.sol

Inherits from: Owned.sol, TokenController. Uses SafeMath for uint256 operations.

This is the contract where the contribution takes place. The first part of the contract declares the variables where the address of the holders will be stored, token, sets the sale limit and the maximum supply of the token.

[L11] SafeMath is specified for the type uint256, this guarantees that all the operations done with uint256 are not in danger of an overflow.
initialized() [L40-43]: Modifier to check if the token contribution is initialized.
TokenContribution() [L45-46]: Contract constructor.
changeController(newController) [L51-54]: The owner can call this method to set the new controller of the contract.
initialize(token, destTokensReserve, destTokensTeam, desTokensBounties, destTokensAirdrop, destTokensAdvisors, destTokensEarlyInvestors) [L59-93]: The owner of the contract can call this function to initialize the token contribution.

[TokenController methods]

generate(th, amount) [L118-126]: The owner of the contract can call this method to generate amount tokens to th address.
finalize() [L150-226]: The owner of the contract can call this method to finalize the contribution. After this method is called the correspondent tokens are sent to their holders.
percent(p) [L228-230]: Does the percentage of a number.
isContract(addr) [L235-242]: Checks if addr is a contract.
tokensIssued() [L250-252]: Returns total tokens issued.
getBlockNumber() [L260-262]: Returns the block number.
getTime() [L265-267]: Returns current time.
claimTokens(token) [L278-291]: This method can be used by the controller to extract mistakenly sent tokens to this contract.
Events [L293-299]: Events used by the contract to emit values.

TokenHolders

All token holders follow the same structure, the only difference is the timing of the collectTokens function:

Inherits from: Owned.sol Uses SafeMath for uint256 operations.

collectedTokens: Amount of tokens collected from the holder.
crowdsale: Address of the token contribution used to check the finalized time.
Minimetoken: Address of the token to do the transfers.
Holder constructor (owner, crowdsale, minimetoken): Constructor of the contract.
collectTokens(): The owner of the contract can call this function to collect tokens. If no tokens are available to collect at the time of call an exception is thrown. The locking period of the tokens differs from the holder. If there are tokens to collect, the amount is transferred to the owner account.
months(m): Returns m amount of months. This is used inside collectTokens to check if the locking period is over.
getTime(): Returns current time.
claimTokens(token): This method can be used by the controller to extract mistakenly sent tokens to this contract.
Events: Events used by the contract to emit values.